Set in Philadelphia, the plot sees Travolta playing a sound-effects recorder who works on cheesy slasher flicks and is told by his producer to re-record a scream. When out recording incidental noises at night, he hears a tyre blow out and sees a car drift off a bridge and sink underwater. He dives in and manages to rescue Allen, who turns out to be a hooker. Her companion drowns, and is soon revealed to be a politician who was in the Presidential nomination race, in a bizarre reversal of the ChappaquiddickTed Kennedy incident. The dead politicians's associates try to cover up the story, pay-off Allen, and the media report that the politician was alone in his car. Travolta keeps his trap shut but stays in contact with the girl.

When Travolta plays back his recording he can ascertain two sounds, and becomes convinced that there was a gunshot before the blow-out. His post-Watergate instinct for conspiracy triggered, he uses his burgeoning relationship with Allen to solve this conundrum, but has difficulty getting anyone to believe his theories, and has his efforts to gather evidence thwarted at each turn.

As usual for de Palma movies, the film is shot beautifully, with imaginative editing, use of split screen and is handy as a primer on the art of sound effect editing. The score by Pino Donaggio is terrific and Travolta is excellent in an interesting part, playing a brighter character then usual, although Allen is less convincing and her ditzy tart sometimes grates.The script is also adventurous, full of black humour and is unafraid to depart from a strict linear format - a device that would later be overused in the 1990s as Tarantino imitations clogged the picturehouses. Tarantino has consistently sung the praises of Blow Out and Travolta's role in this helped bag his career resurrecting role in QT's Pulp Fiction.

Although the plot is more or less an updated spin on Blow-Up the theme of conspiracy and tape recordings more closely reflects The Conversation, another film that tapped into the unease of the American political process after the disillusionment of the JFK assassination, Vietnam and Watergate. However Blow Out is more closely concerned with violence, as shown in the character played by John Lithgow - an idealistic CIA operative who harms psychotically more and more innocents as he attempts to cover his tracks and mistakes. Also supporting is a pre-SipowiczianDennis Franz who plays a blackmailer who acts as Allen's pimp and was involved in attempting to frame the drowned politician.

The films concludes in a cat and mouse chase involving Travolta, Allen, Lithgow during a firework display to celebrate the American Bicentennial, and hilariously features one of the most inept movie car chases. The ending keeping in tone with the rest of the film is downbeat but with a darkly comic touch, at least Travolta now has the scream he requires. This darkness led to the film being largely ignored or dismissed on release, although since then it has been reappraised in a more positive light, and is now viewed as one of the highpoints of De Palma's career (far better than Bonfire of the Vanities and Mission to Mars, a bit behind Carrie and The Untouchables), and was the last memorable film Travolta made before his descent into movies with talking babies and his comeback as an older and fatter actor.